US1581221A - Feeding mechanism for sewing machines - Google Patents

Description

April 20 1926. I 1,581,221 .J.-R. MOFFATT FEEDING MECHANISM FOK SEWING MACHINES Filed July 14, 1921; 2 Sheets-Sheet 1 April 20,1926. 1,581,221

- J.. R. MOFFATT I FEEDING MECHANISM FOR, SEW IBG MACHINES Filed Jqly 1.4 1921 I 2 Sheets-Sheet 2 Patented Apr. 20, 1926.

UNITED STATES JAMES R. Morr'A'r'r, or CHICAGO. ILLINOIS, Assienon 'ro Union SPECIAL MACHINE COMPANY, or CHICAGO, rumors, A ooaroaa'rron or ILLINOIS.

FEEDING MECHANISM non snwme MACHINES.

Application filed July 14, 1921. Serial No. 484,665.

To all whom it may concern:

Be it known that 1, James R. Morra'rr, a citizen of the United States, residing at Chicago, in the county of-Cook, State of Illinois, have invented certain new and useful Improvements in Feeding Mechanisms for Sewing Machines, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

The invention relates to new and useful improvements in feeding mechanisms for sewing machines," and more particularly to a feeding mechanism for a sewing machine having a covering stitch forming mechanisin.

An object of the invention is to provide a feeding mechanism for a machine of the above type, which feeding mechanism in cludes fabric engaging and feeding sections which are capable of yielding relative to other fabric engaging and feeding sections to accommodate varying conditions in the thickness of the seam.

A further object of the invention is to provide a feeding mechanism of the above character wherein the yielding sections are of substantially the same width as the covered seam formed by the stitching mech anism and located in rear of the needles.

A still further object of the invention is to provide a feeding mechanism of the above character wherein the throat plate in rear of the needles is provided with a groove adapted to receive the increased thickness in the seam due to overlapping fabricsections within the limits of the stitching mechanism, and wherein the feeding dog for feeding the material is provided with yielding fabric engaging surfaces adapted to engage the material pressing into said groove, and rigid fabric engaging surfaces disposed at each side of said groove and engaging the fabric at each side of the covering stitches.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings Figure 1 is a plan view of a portion of a sewing machine of the cylinder bed type having my improvements applied thereto; Fig. 2 is a similarview withthe presser foot and other elements above the cloth plate removed;

Fig. 3 is a sectional view on the line 3-3 of Fig. 2;

Fig. {i is a planview of my improved feed which is constructed so as to form a covered seam the edges of the fabric sections being either slightly overlapped or abutted and the fabric sections and a cross thread or threads above'the fabric sections. The overlapping of the fabric sections together with the cross threads form extra thickness in the seam, that is the fabric sections are of greater thickness at the line where they are united than they are back from the covering seam. Considerable difliculty has been experienced in properly feeding the fabric sections owing to this increased thickness in the seam. The'present invention is directed particularly to a feeding mechanism whereinthe fabric'sections not only in the region of the seam but at each side thereof are firmly gripped and fed by the feeding mech-' anism notwithstanding this increased thickness in the seam and even though the thickness in the team should vary by reason of cross seamsor the like extending into the seam joining the fabric sections.

In carrying out the invention either the resser foot or the throat plate is provided with a groove in rear of the needles, and this groove is of sufficient depth and width 'to receive the extra thickness of the seam. The feed dog is provided with rigid fabric engaging sections disposed at opposite sides of the groove and adapted to engage the respective fabric sections at each side of the covering seam. The feed dog is also provided with'yielding fabric engaging sections oined by a plurality of needle threads con. nected by a looper thread or threads below located between the needles and between the I rigid fabric engaging sections which are adapted to engage the fabric sections within the limits of the covering seam. These yielding sections of the feed dog will engage the fabric sections even though they vary in thickness and will firmly grip the same, and thus the fabric sections throughout the region of the seam and at each side thereof will be gripped and fed at each feeding operation.

Referring more in detail to the drawings, I have shown the invention as applied to a cylinder bed type of machine, such as shown in the patent granted to Joseph Berger November 5, 1918, No. 1,283,639. In this type of machine the material is fed off from the end of the arm. The work supporting arm is indicated at 1, and said work supporting arm is provided with a throat plate 2 on which the material rests during stitching. Said throat plate is provided with needle openings 333 through which the needles 4a4t pass. The needles are each provided with a thread and form needle thread loops which are joined on the upper face of the fabric by a cross thread, indicated at in Fig. 7 of the drawings. In this figure the needle threads are indicated at a and theneedle thread loops beneath the fabric sections are connected by a looper thread I). The two fabric sections are indicated at F and F. Said fabric sections, as shown in Fig. 7 are overlapped and the overlapped portions are disposed within the limits of the outer needles which form the needle thread loops aa, hence these outer needle thread loops pass through the respective fabric sections only, while the center needle thread loop passes through both of the fab- "ic sections.

The material is held on the work support by means of a presser foot 5, which presser foot is provided with a yielding section 6. Said presser foot carries a stationary trimming blade 7 with which a movable triniming blade 8 cooperates. The edges of the fabric sections are turned up, and then pass through the guiding slot at the forward end of the presser foot, are trimmed, and are then turned down into overlapped relation for stitching, as more fully disclosed in said Berger patent.

The throat plate 2 is provided with a groove or recess 8. Said recess 8 is located in rear of the opening 9 in the throat plate. The needle openings 3 lead into the opening 9, and stitch forming fingers 10 carried by the throat plate project into said opening 9. The recess 8 is substantially the same width as the opening 9 and the opening 9 is substantially the same width as the stitching mechanism, that is, the distance between the outer faces of the outer needles. The main section 5 of the presser footextends over the recess 8, and the rear end of the recess 8 is slightly in rear of the rear end of the presser foot. The overlapped edge portions of the fabric sections together with threads pass into the recess 8, as clearly shown in Fig. 6. The throat plate is provided with slots 1111 at each side of the recess 8. Said throat plate is also provided with bars 12 between which are slots 12 which open into the recess 8.

The feeding mechanism includes a feed dog 13, said feed dog 13 being formed with a shank 14 which is provided with an elongated opening 15 through which a suitable screw passes for securing the feed dog to the feed bar. Said feed dog has main fabric engaging sections 16 and 17 which are rigidly secured to the shank 1 1. Threaded into theflow-er face of the section 16 is a headed bolt 18, and threaded into the lower face of the section 17 is a headed bolt 19. Mounted on these bolts 18 and 19 is a cross head 20. Said cross head is provided with sleeves encircling the bolts. Coiled springs 21 encircle these sleeves and bear againstt-he heads of the bolts and also against the cross head and operate to yieldin ly lift the cross head. The cross head is provided with fabric engaging sections 22 which extend through the slots 12. These fabric engaging sections 22 are provided with teeth similar to the teeth on the fabric engaging sections 16 and 17. The spring normally raises the cross head until its upper face engages the lower face of the feed bar sections 16 and 17, and when in this position the fabric engaging sections 22 are substantially on the same level as the main fabric engaging sec tions 16 and 17. These fabric engaging section-s 22 operate in the region of only and bear against the overlapped portions of the fabric sections forming the seam.

It will readily be seen that said sections 22 will yield to correspond to varying thicknesses in the seam. The springs 21 are of sufficient tension so that these yielding sections 22 will engage the fabric firmly and cooperate with the sections 16 and 17 in the feeding of the fabric. While the section 22 yields to correspond to the varying thicknesses in the fabric at the lapped portion of the seam, said yielding section has the same longitudinal movement as the main section and will cooperate with said main section in the feeding of the fabric a stitch length. This is accomplished, too, without disturbing the portion of the fabric engaged by the yielding section relative to the portion of the fabric engaged by the rigid sections of the feed dog. The fabric sections will be engaged in rear of the needles and at each side of the needles, as the sections 16 and 17, as clearly shown in Fig. 2, ext-end along side of the needles as well as in rear thereof.

in auxiliary or differential feed dog may be used in conjunction with the feed dog above described and will be located, of

the recess 8.

course, in front of the needles and in front of the fabric engaging sections 16 and 17. V'hile I have shown-the throat plate as provided with a recess and the yielding sections as limited in their upward movement to a position level with the main fabric feeding sections, it will be understood that the arrangement of the recess and of the yielding sections may be varied without departing from the spirit of the invention as set forth in the appended claims, the essential feature consisting in the providing of a clearance space for the seam and of the yielding sections of the feed dog which engage the seam within the limits of the covering stitch forming mechanism.

Vi hile also I have shown the invention as applied to a feed-off-the-arm cylinder type of the work support, from certain aspects of the invention, my improved feeding mechanism may be used with a feednp-the-arm machine or a flat bed type of machine. It will also be apparent that while I have shown and described my improved feeding mechanism as especially adapted for feeding fabric sections which are overlapped and joined by covering stitches, it will be understood that the sections may be abutted and joined by covering sitches instead of overlapped. Where a plurality of cross threads are used or a plurality of lower threads, thus forming considerable thickness to the seam, my improved feeding mechanism will readily take care of the extra thickness and feed the fabric sections uniformly.

Having thus particularly described the invention, what is claimed as new is 1. The combination with a Work support and a presser foot; of a feeding mechanism including a feed dog having main rigid fabric engaging sections, and fabric engaging sections adapted to yield bodily and vertically to accommodate different thicknesses in material, said yielding section having the same longitudinal movement as the main rigid sections.

2. The combination with a work support and a presser foot; of a feeding mechanism including main rigid fabric feeding sections, and fabric engaging sections disposed between said rigid fabric feeding sections and adapted to yield vertically to accommodate material of varying thicknesses, said yielding section having the same longitudinal movement as the main rigid sections.

3. The combination with a work support, a plurality of needles, and a presser foot; of a feeding mechanism including yield vertically to accommodate the overlapped edges of fabric sections being fed to the needles. v

4. The combination of a work support, a throat plate carried thereby, said throat plate having needle openings formed therein, and a recess in rear of said needle openings of substantially the same width as the distance between the outer needle openings, a plurality of needles, and a feeding mechanism including rigid fabric feeding sections at each side of said recess and needles, and yielding fabric feeding sections adapted to engage the "fabric sections passing through said recess. s

V 5. A feed dog for sewing machines comprising a supporting shank, main rigid spaced fabric engaging sections carried thereby, fabric engaging sections located between said rigid fabric engaging sections, and means for supporting the fabric engaging section located between the rigid sections, whereby said central section can yield bodily and vertically, said yielding section being mounted upon the shank of the feed dog and having the same longitudinal movement as the main rigid sections of the feed dog.

6. A feed dog for sewing machines comprising a supporting shank, spaced main fabric engaging sections rigidly carried by said shank, fabric engaging sections located between said rigid sections, and means for supporting said intermediate fabric engaging sections from said rigid fabric engaging sections whereby said intermediate fabric en gaging section may yield vertically-to accommodate overlapped fabric sections being fed thereby, said yielding section having the same longitudinal movement as the main.

fabric engaging sections.

7. A feed dog comprising a supporting shank, spaced rigid fabric engaging sections, headed bolts carried thereby, a cross head having sleeves sliding on said bolts, springs surrounding said sleeves and engaging the cross head for raising the cross head, fabric engaging sections carried by the cross head and disposed intermediate the rigid fabric engaging sections.

In testimony whereof, I affix my signature.

JAMES R. MOFFATT.

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